dependency_optimization: Control dependency optimizations. Remove
redundant control dependencies, which may enable other optimization.
This optimizer is also essential for pruning Identity and NoOp nodes.

loop_optimization: Loop optimizations.

function_optimization: Function optimizations and inlining.

debug_stripper: Strips debug-related nodes from the graph.

disable_model_pruning: Disable removal of unnecessary ops from the graph

scoped_allocator_optimization: Try to allocate some independent Op
outputs contiguously in order to merge or eliminate downstream Ops.

pin_to_host_optimization: Force small ops onto the CPU.

implementation_selector: Enable the swap of kernel implementations based
on the device placement.